Visual prey detection by near-infrared cues in a fish

Abstract

Many animal species are able to perceive light wavelengths beyond those visible to humans. While numerous species are additionally sensitive to short wavelengths (UV), long wavelengths such as the near-infrared spectrum (NIR) are supposed to be unsuitable for visual perception. Here, we experimentally show that under exclusive NIR illumination, the cichlid fish Pelvicachromis taeniatus displays a clear foraging response towards NIR reflecting prey. Additional control experiments without prey indicate that the observed behavior is not a mere response to the NIR environment. These results give first evidence for NIR visual sensitivity in a functional context and thus challenge the current view about NIR perception.

Notes

Acknowledgments

This research was funded by the Deutsche Forschungsgemeinschaft (BA 2885/2-3, TH 1615/1-1). We are grateful to Simon Vitt for the initial stimulus he gave us to work on infrared perception, Kathrin Langen for fish maintenance, and the Bakker Research Group for the discussion.